Firstly, what is your vision for the future of this tree. (style or rough outline of silhoutte)
Are you still building trunk girth?
You probably want to eliminate all but one of those 4 branches, however now is not a great time of year to initiate very large cuts. One thing you could do is remove the smallest branch completely (but leave a stub about 1/2 inch long) and reduce the length of the other three branches. I'd probably cut them a couple of inches off the trunk.
The exception might be if you are going for a broom style, in which case having 4-5 primary branches coming out of a single point is pretty much ideal. But even for this style, the larger branches (and the trunk) are quite thick beyond the point at which all of the broom branchlets split. If you are considering this style, I'd probably cut all of those branches about 1-2 inches from the trunk, but leave the trunk as is. Then come back next spring and do a trunk chop right above your broom point.